Lateralization of amygdala activation in fMRI may depend on phase-encoding polarity
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Susceptibility artifacts along the phase-encoding (PE) direction impact the activation pattern in the amygdala and may lead to systematic asymmetries. We implemented a triple-echo echo-planar imaging (EPI) sequence, acquiring opposite PE polarities along left–right PE direction in a single shot, to investigate its effects on amygdala lateralization.
Materials and Methods
Twelve subjects viewed emotional faces to evoke amygdala activation.
Results and Conclusion
A region of interest analysis revealed that the lateralization of amygdala responses depended on the PE polarity thus representing a pure method artifact. Alternating PE with multi-echo EPI reduced the artifact. Lateralized fMRI activation in areas with magnetic field inhomogeneities need to be interpreted with caution.
KeywordsAmygdala Lateralization Distortion correction Multi-echo fMRI
Blood-oxygenation level dependent
Functional magnetic resonance imaging
Modified driven equilibrium Fourier transform
Montreal Neurological Institute
Region of interest
Statistical parametric mapping
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